応用水文 = Applied hydrology

第12次 아시아ㆍ太平洋 矯政局長會議 參加記

The biochemical composition of dissolved organic matter (DOM) strongly influences its biogeochemical role in freshwater ecosystems, yet DOM composition measurements are not routinely incorporated into ecological studies. To date, the majority of studies of freshwater ecosystems have relied on bulk analyses of dissolved organic carbon and nitrogen to obtain information about DOM cycling. The problem with this approach is that the biogeochemical significance of DOM can only partially be elucidated using bulk analyses alone because bulk measures cannot detect most carbon and nitrogen transformations. Advances in fluorescence spectroscopy provide an alternative to traditional approaches for characterizing aquatic DOM, and allow for the rapid and precise characterization of DOM necessary to more comprehensively trace DOM dynamics. It is within this context that we discuss the use of fluorescence spectroscopy to provide a novel approach to tackling a longstanding problem: understanding the dynamics and biogeochemical role of DOM. We highlight the utility of fluorescence characterization of DOM and provide examples of the potential range of applications for incorporating DOM fluorescence into ecological studies in the hope that this rapidly evolving technique will further our understanding of the biogeochemical role of DOM in freshwater ecosystems.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2010.55.6.2452

Fluorescence spectroscopy opens new windows into dissolved organic matter dynamics in freshwater ecosystems: A review

Improvement and expansion of the Fmask algorithm: cloud, cloud shadow, and snow detection for Landsats 4–7, 8, and Sentinel 2 images

13. 벼잎선충의 약제처리 방법별 방제 효과

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Load Estimator (LOADEST): A FORTRAN Program for Estimating Constituent Loads in Streams and Rivers

................................................................................................................................................................... 1.0 Introduction ........................................................................................................................................................ 1.1 Model Enhancements ........................................................................................................ ................................... 2 1.2 Report Organization ............................................................................................................................... 3 1.3 Acknowledgments ........................................................................................................... .................................... 3 2.0 Theory ................................................................................................................................................................ 2.1 Background Transient Storage Models .............................................................................................. 4 2.2 Governing Differential Equations ........................................................................................................... 5 2.2.1 Processes Considered / Model Assumptions ................................................................................ .......... 5 2.2.2 Time-Variable Equations ................................................................................................. ....................... 6 2.2.3 Steady-State Equations ............................................................................................................ 7 2.3 The Conceptual System ........................................................................................................................ 8 2.4 Numerical Solution Time-Variable Equations .............................................................................. ..................... 8 2.4.1 Finite Differences ...................................................................................................................... 8 2.4.2 The Crank-Nicolson Method .................................................................................................... 10 2.4.3 Main Channel Solute Concentration ....................................................................................... . 10 2.4.4 Storage Zone and Streambed Sediment Concentrations ................................................................. 12 2.4.5 Decoupling the Main Channel, Storage Zone, and Streambed Sediment Equations ....................... 2.5 Numerical Solution Steady-State Equations ...................................................................................... 14 2.6 Boundary Conditions ....................................................................................................... .................................... 15 2.6.1 Upstream Boundary Condition ................................................................................................. 15 2.6.2 Downstream Boundary Condition ............................................................................................ 15 2.7 Parameter Estimation ...................................................................................................... ..................................... 16 3.0 User’s Guide ............................................................................................................... ..................................................... 2 3.1 Applicability ............................................................................................................. ........................................... 20 3.2 Model Features ...................................................................................................................................... 20 3.2.1 Simulation Modes: Time-Variable and Steady-State ....................................................................... 20 3.2.2 Conservative and/or Nonconservative Solutes ............................................................................. 21 3.2.3 Flow Regimes ........................................................................................................................... 21 3.2.4 Parameter Estimation using OTIS-P ........................................................................................ 22 3.3 Conceptual System, Revisited .............................................................................................................. 22 3.4 Input/Output Structure .................................................................................................... ..................................... 24 3.4.1 OTIS ........................................................................................................................................... 24 3.4.2 OTIS-P ....................................................................................................................................... 25 3.5 Input Format ........................................................................................................................................... 26 3.5.1 Units ........................................................................................................................................... 26 3.5.2 Internal Comments .................................................................................................................... 27 3.5.3 The Control File ......................................................................................................................... 27 3.5.4 The Parameter File ...................................................................................................... ............................ 29 3.5.5 The Flow File ............................................................................................................................. 35 3.5.6 The Data File (OTIS-P only) ............................................................................................. ..................... 40 3.5.7 The STARPAC Input File (OTIS-P only) .................................................................................... 41 3.6 Model Execution ..................................................................................................................................... 43 3.6.1 OTIS ........................................................................................................................................... 44 3.6.2 OTIS-P ....................................................................................................................................... 44 3.7 Output Analysis ...................................................................................................................................... 45 3.7.1 The Solute and Sorption Output Files ..................................................................................... 45 3.7.2 The Post-Processor .................................................................................................................. 46 3.7.3 Plotting Alternatives .................................................................................................................. 47 4.0 Model Applications ......................................................................................................... ................................................ 48 4.1 Application 1: Conservative Transport (OTIS) ............................................................................. ...................... 48

/pdf/one-dimensional-transport-with-inflow-and-storage-otis-a-5cges40f02.pdf

One-Dimensional Transport with Inflow and Storage (OTIS): A Solute Transport Model for Streams and Rivers

[1] An in-stream injection of two dissolved organic acids (phthalic and aspartic acids) was performed in an acidic mountain stream to assess the effects of organic acids on Fe photoreduction and H2O2 cycling. Results indicate that the fate of Fe is dependent on a net balance of oxidative and reductive processes, which can vary over a distance of several meters due to changes in incident light and other factors. Solution phase photoreduction rates were high in sunlit reaches and were enhanced by the organic acid addition but were also limited by the amount of ferric iron present in the water column. Fe oxide photoreduction from the streambed and colloids within the water column resulted in an increase in the diurnal load of total filterable Fe within the experimental reach, which also responded to increases in light and organic acids. Our results also suggest that Fe(II) oxidation increased in response to the organic acids, with the result of offsetting the increase in Fe(II) from photoreductive processes. Fe(II) was rapidly oxidized to Fe(III) after sunset and during the day within a well-shaded reach, presumably through microbial oxidation. H2O2, a product of dissolved organic matter photolysis, increased downstream to maximum concentrations of 0.25 μM midday. Kinetic calculations show that the buildup of H2O2 is controlled by reaction with Fe(II), but this has only a small effect on Fe(II) because of the small formation rates of H2O2 compared to those of Fe(II). The results demonstrate the importance of incorporating the effects of light and dissolved organic carbon into Fe reactive transport models to further our understanding of the fate of Fe in streams and lakes.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2002WR001768

Transport and cycling of iron and hydrogen peroxide in a freshwater stream: Influence of organic acids

A review of various metrics used to characterize transient storage indicates that none of the existing measures successfully integrate the interaction between advective velocity and the transient storage parameters (storage zone area, storage zone exchange coefficient). Further, 2 existing metrics are related to mean travel time, a quantity that is independent of the storage zone exchange coefficient, α. This interaction and the effect of α on travel time are important considerations when determining the mass of solute entering the storage zone within a given reach. A new metric based on median reach travel time is therefore proposed. Median reach travel time due to advection–dispersion and transient storage, and median reach travel time due solely to advection–dispersion are computed based on numerical simulations. These 2 travel times are used to determine Fmed, the fraction of median travel time due to transient storage. Application of the new metric to 53 existing parameter sets indicates that...

Robert L. Runkel

Papers

Load Estimator (LOADEST): A FORTRAN Program for Estimating Constituent Loads in Streams and Rivers

One-Dimensional Transport with Inflow and Storage (OTIS): A Solute Transport Model for Streams and Rivers

Transport and cycling of iron and hydrogen peroxide in a freshwater stream: Influence of organic acids

A new metric for determining the importance of transient storage

Assessment of metal loads in watersheds affected by acid mine drainage by using tracer injection and synoptic sampling: Cement Creek, colorado, USA